(a) Field of the Invention
The present invention relates to an improved key structure for computer keyboards, and more particularly to an improved key structure comprising two crossed support frames pivotally connected, a key unit, and a keyboard base. The support frames have center limiting rods projecting respectively from outer sides of their connecting position. Left and right slide rods respectively project from both sides of a horizontal rod at a bottom end of the two crossed support frames, with an inverted U-shaped groove disposed at a middle section. Two opposite slide bars that orient inwardly are provided on upper ends of the crossed support frames. The key unit has two parallel arrays of slide holes on left and right sides thereof respectively. The keyboard base has a notch of a suitable width at each of left and right sides thereof. A limiting plate extends inwardly on each of the left and right notches. Inverted L-shaped grooves with openings orienting in opposite directions are provided on left and right ends of the front and rear sides. Two vertical rods are respectively provided at a middle section between left and right inverted L-shaped slide grooves, with a vertical slide track formed between the two vertical rods, so that the four bars of the two crossed support frames can be disposed in the four slide holes of the key respectively, and the four slide rods can be disposed in the four inverted L-shaped slide grooves of the key base. At the same time, the left and right inverted U-shaped grooves straddle on the left and right limiting plates, whereas the center limiting rods on both sides are just located on the two vertical slide tracks. When the key is pressed, it compresses an elastic silicon rubber, so that the two crossed support frames utilize the center limiting rods as pivots and drop along the vertical slide tracks, forcing the four slide bars and the four slide rods to displace outwardly in the four slide holes of the key and the four inverted L-shaped slide grooves of the key base, hence the crossed support frames are compressed and lie flat in the key base in an overlapping manner. In this way, the key will not deviate or tilt. Besides, the thickness between the key and the base plate can be reduced.
(b) Description of the Prior Art
With conventional computer keyboards, in order to obtain a suitable height between the keys and the base plate and to ensure smooth operation, improvements have been made on the structure between the keys and the base plate so as to meet the demand of the industry. Crossed links have been used in the industry. However, most of the crossed links have upper and lower ends movably provided at fixed points on one side thereof, and upper and lower ends capable of horizontal sliding displacement on the other side. When a key is pressed, the side capable of horizontal sliding displacement is likely to sink in advance so that it is in a slanting state, thus dragging the center point. This often results in deflection or deviation or slanting, which is inconvenient to the user during operation.